Ultrasonic Testing Of Residual Stress Of TC4 Titanium Alloy Ring Rolling Parts

Titanium alloys are widely used in various fields due to their high strength,good corrosion resistance and heat resistance.TC4 titanium alloy is often formed by forging,and the existence of residual stress in the TC4 material of the aero-engine makes the machining deformation and fatigue life decrease.Therefore,it is necessary to develop a non-destructive and rapid method for measuring residual stress of ring rolling parts for product quality control.In this thesis,the TC4 material for aeroengine engine ring rolling was taken as the research object.Based on the principle of acoustic elasticity,the ultrasonic residual stress detection system was designed and built.The Critical Refraction Longitudinal wave sound field and parameter selection and optimization of the probe incident angle and detection frequency and probe spacing design are simulated by CIVA simulation,tensile and compression tests were used to establish the relationship between the stress and ultrasonic propagation time of TC4 materials.The self-designed and made C-ring test block was verified by X-ray diffraction residual stress measurement.The residual stress test of TC4 actual ring rolling parts was based by this relationship,and the residual stress changes before and after shot peening of TC4 ring rolling parts were compared and analyzed.The conclusions are as follows:(1)The theoretical calculation,CIVA simulation and experimental test obtained the optimal parameters of the critical refracting longitudinal wave probe.The stressultrasonic time relationship was verified by the tensile and compression tests,and The values of the tensile stress coefficient was basically the same as the compressive stress coefficient.(2)The critical surface stress of TC4 titanium alloy C-ring specimen is detected by the critical refracting longitudinal wave method and X-ray diffraction method.The measurement results of the two are basically the same.(3)The residual stress of the actual TC4 titanium alloy ring rolling was tested by the critical refracting longitudinal wave stress detection system designed in this paper.The stress distribution obtained by the test is basically the same as the simulation result.(4)Residual stress of the TC4 titanium alloy compressor fan of the aeroengine before and after shot peening was measured,the residual tensile stress after shot peening was significantly less than that before the shot,which is consistent with the shot peeningprinciple,which indicates the self-designed LCR wave residual stress detection system and the detection method in this paper is completely correct.The research results of this paper can be directly used to measure the residual stress in the production of TC4 ring rolling parts,provide reference for improving the process of ring rolling parts,and provide an effective new means for quality control of ring rolling parts.